Crushing apparatus having centrifugal classifier

ABSTRACT

Crushing apparatus having a centrifugal classifier comprising a first housing and a second housing which are substantially coaxial with each other. The first housing contains hammer means rotatable about its axis and is provided with a chute for feeding thereto the material to be crushed. The second housing has discharge means proximate to its axis. The first housing communicates with the second housing through first conduit means and second conduit means.

v United States Patent Maeda et al. Nov. 4, 1975 CRUSHING APPARATUSHAVING 2,939,638 7/1960 Haigh et al. 241/55 x CENTRIFUGAL CLASSIFIER3,173,618 3/1965 Merges et al. 24l/55 Inventors: Hiroyuki Maeda,Nishinomiva;

Teruaki Suzuki, Kadoma, both of Japan Osaka Gas Company, Ltd. &Kabushiki Kaisha Hosokawa Funtai Kogaku Kenkyusho, Osaka, Japan Filed:Sept. 16, 1974 Appl. No.: 506,532

[73] Assignee:

Int. Cl. B02C 13/08; B02C 13/13 Field of Search 241/52, 55, 79.1, 80

[56] References Cited UNITED STATES PATENTS 2,522,027 9/1950 Evans241/52 X Primary Examiner-Granville Y. Custer, Jr. Assistant ExaminerE.F. Desmond Attorney, Agent, or Firm-Edwin E. Greigg [57] ABSTRACTCrushing apparatus having a centrifugal classifier comprising a firsthousing and a second housing which are substantially coaxial with eachother. The first housing contains hammer means rotatable about its axisand is provided with a chute for feeding thereto the material to becrushed. The second housing has discharge means proximate to its axis.The first housing communicates with the second housing through firstconduit means and second conduit means.

9 Claims, 7 Drawing Figures I 17 I6 g -Q y 18 5 14 i 17 U.S. Patnt Nov.4, 1975 Sheet 1 of2 3,917,175

U.S. Patent Nov. 4, 1975 Sheet 2 of2 3,917,175

CRUSl-IING APPARATUS HAVING CENTRIFUGAL CLASSIFIER BACKGROUND OF THEINVENTION The present invention relates to a crushing apparatus having acentrifugal classifier in which material of different kinds to becrushed are crushed by hammer means and the crushed material isclassified into coarse fragments and fine fragments, of which the finefragments are selectively discharged from the apparatus in succession.

Generally, when a material is crushed by rotating hammer means, it isnot always wholly crushedinto fine fragments in uniformity by the hammermeans within a short time. Accordingly, it is necessary to classify thecrushed fragments according to the size and to crush the coarsefragments with the hammer means again.

Accordingly, the conventional process is such that the material fed intothe crushing apparatus is crushed by hammer means, and all of itscrushed fragments are discharged outside thecnushing apparatus to beclassified according to the size by a separately provided classifyingapparatus. Thereafter, the coarse fragments alone are returned to thecrushing apparatus to be crushed again. In the course of such repeatedoperation the fine fragments are selectively taken out.

However, the conventional process as described above requires, apartfrom the power for rotating the hammer means of the crushing apparatus,the power for operating the classifying apparatus and, afterclassification, returning the coarse fragments to the crushingapparatus.

Thus, the overall apparatus not only tends to be large and complex butentails a considerable power waste; its operation is not economical.

SUMMARY OF THE INVENTION This invention intends to eliminate theforegoing drawbacks by making full use of the functions of the hammermeans and provide an economical crushing apparatus equipped with acentrifugal classifier which is capable of efficiently performing bothcrushing and classifying operations.

The crushing apparatus having a classifier of this invention comprises afirst housing and a second housing substantially coaxial with eachother; first conduit means and second conduit means for communicatingthe first housing and the second housing, the first conduit means beingconnected to both the housings at a position proximate to the peripheralwalls thereof and having an inner space having an annular cross section,the second conduit means being connected to both the housings at aposition closer to the axis of the housings than the first conduitmeans; hammer means disposed within the first housing and rotatableabout its axis; a chute connected to the first housing at a positioncloser to the axis than the first conduit means; and vdischarge meansconnected to the second housing at a position closer to the axis thanthe second conduit means.

The rotation of the hammer means produces in the first housing awhirling gasstream, which flows through the first conduit means into thesecond housing and cir- The material fed into the first housing iscrushed by the hammer means and is then sent by the gas stream throughthe first conduit means into the second housing, in which it circulatesabout its axis and is classified into coarse fragments and finefragments by the cooperative action of the centrifugal force and theconveying force of the gas stream. The fine fragments are sent to thedischarge means by the gas stream, whereas the coarse fragments are sentby the gas stream back into the first housing through the second conduitmeans. In other words, the material is crushed into fragments within thefirst housing and such fragments of all sizes are promptly sent to thesecond housing through the first conduit means. The fragments are thenmade to circulate together with the gas stream in the second housing andare effectively classified into coarse fragments and fine fragments bythe cooperative action of the centrifugal force and the conveying forceof the gas stream.

Since the gas stream generated by the rotation of the hammer means isused to obtain a whirling flow for classifying the crushed fragments,the economy of overall power is made possible by efficiently using theenergy from the hammer means.

After classified, the fine fragments are promptly let out of theapparatus on the gas stream through the discharge means, whereas thecoarse fragments are returned through the second conduit means to thefirst housing by the gas stream. In this instance as well, an effectiveuse is made of the differentiation of pressure within the first housingcaused by the rotation of the hammer means. To state this in moredetail, since the second conduit means is disposed closer to the axis ofboth the housings than the first conduit means, the pressure in thevicinity of the opening of the second conduit means to the first housingis higher than that in the vicinity of the opening thereof to the secondhous- Accordingly, after classified, the coarse fragments circulatingvnear the opening of the second conduit means to the second housing arepositively and smoothly returned to the first housing owing to theinhaling force caused by the aforesaid pressure differentiation.

In this way the inhaling force caused by the pressure differentiationwhich is brought about by the rotation of the hammer means is used forthe feed-back of the coarse fragments to the first housing, whereby afurther economy of power is made possible.

As stated above, the apparatus according to the present invention usesthe inhaling force caused by the pressure differentiation owing to therotation of the hammer means which is the essential factor of a crushingapparatus.

Therefore, not only its construction is simple but it is positivelycapable of both crushing and classifying with a small power supply, andits running cost will be low.

' In addition, the coarse fragments introduced through the first conduitmeans into the second housing travel to the inlet of the second conduitmeans in circulating motion within the second housing owing to the gasstream and the centrifugal force, instead of proceeding directlythereto.

In the course of this travel, the fragments are cooled by being exposedto the gas stream. This amounts to a secondary advantage, namely theprevention of overheating in crushing heat-sensitive material.

A primary object of this invention is to provide an economical apparatuswith a simple construction and classifying its fragments by a smallpower supply.

Another object of this invention is to provide an apparatus which isdesigned to discharge the fragments of substantially uniform sizeirrespective of the kind of the material.

Still another object of this invention is to provide an apparatus whichis capable of controlling, as desired, the size of the crushed fragmentsof the material to be discharged from the apparatus.

Other objects and advantages of this invention will become more apparentfrom the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation in verticalsection showing an embodiment of this invention;

FIG. 2 is a view in section taken along the line IIII in FIG. 1;

FIG. 3 is a view in section taken along the line III-III in FIG. 1;

FIGS. 4 and 5 are fragmentary side elevations in vertical sectionshowing the principal part of another embodiment;

FIG. 6 is a view in section taken along the line VI-VI in FIG. 5; and

FIG. 7 is a fragmentary side elevation in vertical section showing theprincipal part of still another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show a firsthousing 1 constituting a crushing apparatus and a second housing 2constituting a centrifugal classifier. The first housing 1 and secondhousing 2, both cylindrical, have substantially the same diameter andare coaxially arranged adjacent to each other.

Disposed within the first housing 1 in alignment with its axis 3 is arotary shaft 4 driven by a motor (not shown) and having hammer means 5fixed thereto. The hammer means 5 comprises a disc 6 keyed to the rotaryshaft 4 coaxially therewith and a plurality of crushing blades 7 securedto the periphery of the disc 6 with substantially equal spacingtherebetween. The first housing '1- is formed, over its entire innerperiphery, with a serrated impact crushing surface 8 which is opposed tothe track of revolution of the crushing blades 7. The crushing blades 7and impact crushing surface 8 combine to crush the material fed to theinterior of the first housing 1.

A side partition plate 9 disposed between the first housing 1 and thesecond housing 2 is in the form of a disc and is coaxial with the rotaryshaft 4. Between the outer periphery of the partition plate 9 and theinner peripheral surfaces of the first housing 1 and second housing 2,an annular space is formed which serves as first conduit means 10. Theside partition plate 9 has circular arc apertures which are arrangedcircumferentially about the axis 3 and spaced apart from each other. Theapertures serve as second conduit means 13. The partition plate 9 issecured to a side wall 12 of the secondhousing 2 by bolts and nuts 11.

Alternatively, the second conduit means 13 may be in the form of acontinuous annular aperture centered about the axis 3. In this case, theinner portion of partition plate 9 is secured to the side walll2 of thesecond housing 2 by bolts and nuts.

partition plate 9 is provided with a chute 15 for feeding material intothe first housing 1. The chute I5 commu-. nicates with the first housing1 through an opening 16 in the side wall 14. The opening 16 ispositioned closer to the axis 3 than the first conduit means 10.

A plurality of guide vanes 17 for guiding the gas which comes from thefirst housing 1 into the second housing 2 in the form of a whirlingstream are provided in the interior of the second housing 2 atsubstantially equal spacing along the first conduit means 10 inproximity to its opening.

The number thereof is determined so as to allow the gas streamintroduced through the first conduit means 10 to enter at a unfiormangle over the entire circumference.

The guide vanes 17 are attached to the side wall 12 of the secondhousing 2 by pins provided adjacent to the first conduit means 10, eachof the vanes 17 being fixed or pivotable as desired about an axisapproximately in parallel to the axis 3.

The inner surface of side wall 12 of the second housing 2 is in the formof a slanting wall surface 18 which i slants toward the axis 3, and theside wall 12 has an opening coaxial with the axis 3. Discharge means 19is fixed to the open portion of the side wall 12. The interior space ofthe second housing 2 is therefore constricted toward the axis 3. Theopening of the first conduit means 10 to the second housing 2 ispositioned further into the second housing 2 than the opening of thesecond conduit means 13 to the second housing 2 so as to be disalignedwith the latter stepwise in the direction parallel to the axis3.

The apparatus of the foregoing construction operates in the followingmanner. The material fed to the first housing 1 from the chute 15 isfirst crushed by the impact force of crushing blades 7 of the hammermeans 5 and further crushed into smaller pieces by being forced againstthe impact crushing surface 8. At this time, the high-speed rotation ofthe hammer means 5 produces in the first housing 1 a whirling gasstream, which is guided through the first conduit means 10 into thesecond housing 2 by the guide vanes 17. The gas introduced intothesecond housing 2 and turning in eddy current then partially flowsthrough the second conduit means 13 into the first housing 1 owing tothe pressure gap between the first housing 1 and the second housing 2which is produced by the rotation of the hammer means 5, whilst theremainder of the gas flows out of the second housing 2 via the dischargemeans 19.

Accordingly, the material crushed in the first housing 1, whether coarseor fine, is discharged from the first housing 1 into the second housing2 through the first conduit means 10 as carried on the whirling gasstream produced by the rotation of the crushing blades 7. The crushedfragments sent into the second housing 2 are made to circulate about theaxis 3 on the gas stream: 1 therein and are classified into coarsefragments and fine fragments by the cooperative action of centrifugal 1force and the conveying .force of the gas stream acting toward the axis3.

More specifically, both the fine fragments and the coarse fragments.have the tendency of flowing toward the discharge means 19 while beingcirculated by the gas stream. The centrifugal force acting on thecrushed material owing to the circulatory motion is such that thecoarser the fragments, the greater the force, whereas the finer thefragments, the smaller the force. With fine fragments, therefore, theforce to convey the fragments toward the discharge means 19 overcomesthe centrifugal force, with the result that the fine fragments are letout of the apparatus through the discharge means 19. With coarsefragments, on the other hand, the conveying force toward the dischargemeans 19 comes into balance with the centrifugal force, permitting thecoarse fragments to continuously circulate in the vicinity of the inletof the second conduit means 13. Consequently, the coarse fragments arereturned to the interior of the first housing 1 through the secondconduit means 13 by being withdrawn owing to the pressure gap betweenthe two housings 1, 2 produced by the rotation of the hammer means 5within the first housing 1. In this case, since the construction is suchthat the openings of the two conduit means 10, 13 to the second housing2 are disaligned stepwise and the inner surface of the side wall 12 ofthe second housing 2 is formed into the slanting wall surface 18 asdescribed hereinbefore, the coarse fragments will reach the opening ofthe second conduit means 13 by the combination of the conveying force ofsaid slanting wall surface 18 acting toward the partition plate 9 andthe centrifugal force, without'relying on the inhaling force caused bythe pressure gap between the two housings 1, 2, and then return to theinterior of the first housing 1 smoothly.

The coarse fragments sent from the first conduit means 10 into thesecond housing 2 get cooled by the whirling gas stream whileprogressivelyproceeding toward the second conduit means 13 incirculation. This is particularly advantageous when processing aheat-sensitive material.

The coarse fragments are then crushed again by the hammer means 5 intosmaller fragments, which are sent into the second housing 2 by way ofthe first conduit means 10. In this way the crushing operation iscarried out effectively, permitting fine fragments alone to be drawn outof the discharge means 19.

The angle of the guide vanes 17 is variable to adjust the magnitude ofspeed component for sending the crushed material in the second housing 2toward the axis 3. This makes it possible to control the particle sizeof the material to be withdrawn from the discharge means 19.

FIG. 4 shows another embodiment in which, as seen in vertical sectionalong a plane passing through the axis 3, the inner surface of outerportion of second conduit means 13 defining the interior space thereofis in the form of a slanting surface 21 which flares toward the firsthousing 1 with respect to the axis 3. The slanting surface 21 serves tosmoothly return the circulating coarse fragments in the second housing 2to the first housing 1.

Furthermore, the slanting surface 21 of the second 6 throughthe secondconduit means 13 can be brought to the suitable crushing position moreaccurately to ensure effective crushing operation.

FIGS. 5 and 6 show another embodiment in which the side partition plate9 of annular shape is provided with a barrier plate 20 adjacent theretorotatable in a circumferential direction by a handle 22. When rotated,the barrier plate 20 changes the size of the opening of the secondconduit means 13 and thereby controls the amount of the coarse fragmentsto be returned from the second housing 2 to the first housing 1.

If for example a large quantity of coarse fragments are sent from thefirst housing 1 into the second housing without being finely divided,the barrier plate 20 is adjusted to enlarge the opening of the secondconduit means 13. This increases the quantity of the fragments sent backinto the first housing 1, in which the material is further crushed tosmaller sizes and then discharged into the second housing 2.

FIG. 7 shows another embodiment which is adapted to control the quantityof the fragmentsto be returned to the first housing 1 as in FIGS. 5 and6. A barrier plate 20 operable from outside the apparatus by a handle 22is fixedly provided over the inner peripheral surface of the annularsecond conduit means 13' and is movable in the direction of axis 3. Theinterior space of the second conduit means 13 enlarges toward the firsthousing l. The barrier plate 20, when moved, controls the size of theopening of the interior space of the second conduit means 13.

Indicated at 23 is a guide which is secured to the side wall 12 by boltsand nuts or the like.

Though in the embodiment described herein the side partition plate 9serves dually as one of the side walls of the first housing 1 and thatof the second housing 2, it is possible to arrange the two housings 1, 2at a suitable distance from each other by providing each of the housingswith a side wall plate. The single side partition plate 9 serving duallyas in said embodiment, of course, helps simplify the construction. Inaddition, other merits as below may be expected.

When crushing materials which have brittleness at low temperature suchas rubber, plastics, etc., they are usually refrigerated by means ofrefrigerant prior to feeding into the crushing apparatus. In the case ofprocessing such refrigerated material in a crushing apparatus and aclassifying apparatus with some distance therebetween, the coarsefragments of the crushed material to be returned to the crushingapparatus are liable to warm up during their return trip, making itdifficult to crush at the second round. In order to remove this setbackan extra apparatus for cooling the coarse fragments is required, whichis a disadvantage in respect of equipment and economy. The coarsefragments are effectively prevented from warming up by partitioning thetwo adjacent housings l, 2 with the single partition plate 9 asdescribed hereinbefore. Furthermore, said coarse fragments are exposedto the gas stream within the second housing 2 and are expected to remaincool. Thus a low consumption of the refrigerant for precooling thematerial is assured, and the addition of a cooling means is notrequired, which amount to an advantage in respect of economy andequipment.

What we claim is:

1. A crushing apparatus having a centrifugal classifier comprising:

a first housing and a second housing substantially co= axial with eachother,

first conduit means and second conduit means for communicating the firsthousing and the second housing, the first conduit means being'connectedto both the housings at a position proximate to the peripheral wallsthereof and having an annular cross section, the second conduit meansbeing connected to both the housings at a position closer to the axis ofthe housings than the first conduit means,

hammer means disposed within the first housing and rotatable about itsaxis, a chute connected to the first housing at a position closer to theaxis than the first conduit means, and

discharge means connected to the second housing at a position closer tothe axis than the second conduit means,

the first conduit means permitting a whirling gas stream produced in thefirst housing by the rotation of the hammer means to flow into thesecond housing and circulate about its axis therein, the second conduitmeans permitting a portion of the circulating gas to flow into the firsthousing, the discharge means serving to let the remainder of thecirculating gas out of the second housing, whereby a material fed to theinterior of the first housing is crushed by the hammer means and is thensent by the gas through the first conduit means into the second housingto circulate about its axis therein, the circulating material isclassified into coarse fragments and fine fragments by the cooperativeaction of centrifugal force and conveying force of the gas stream, thefine fragments are sent to the discharge means by the gas stream and thecoarse fragments are sent through the second conduit means into thefirst housing by the gas stream.

2. An apparatus as set forth in claim 1 wherein a plurality of guidevanes for the gas stream are provided in the interior of the secondhousing in proximity to an opening of the first conduit means, each ofthe guide vanes being fixable and pivotable about an axis sub stantiallyparallel to the axis of the second housing.

3. An apparatus as set forth in claim 1 wherein a barrier plate isprovided to open the second conduit means to a variable extent.

4. An apparatus as set forth in claim 1 wherein an inner side surface ofthe second housing provided with the discharge means and opposed to theconduit means is slanted to constrict the interior space of the secondhousing toward the axis.

5. An apparatus as set forth in claim 1 wherein an opening of the firstconduit means to the second hous ing is positioned further into thesecond housing than a corresponding opening of the second conduit means.

6. An apparatus as set forth in claim 1 wherein an outer edge portion ofthe second conduit means protrudes into the first housing.

7. An apparatus as set forth in claim 1 wherein, the

inner surface of an outer portion of the second conduit means is slantedwith respect to the axis of the housings to enlarge the interior spaceof the second conduit means toward the first housing.

8. An apparatus as set forth in claim 1 wherein both the conduit meansare defined by a partition plate separating the housings from eachother.

9. An apparatus as set forth in claim 1 wherein a plurality of guidevanes for the gas stream are provided in second conduit means, an outeredge portion of the second conduit means protrudes into the firsthousing,

and, along a plane passing through the axis, the inner surface of theouter portion of the second conduit means is slanted with respect to theaxis of the housing to enlarge the interior space of the second conduitmeans toward the first housing.

1. A crushing apparatus having a centrifugal classifier comprising: afirst housing and a second housing substantially coaxial with eachother, first conduit means and second conduit means for communicatingthe first housing and the second housing, the first conduit means beingconnected to both the housings at a position proximate to the peripheralwalls thereof and having an annular cross section, the second conduitmeans being connected to both the housings at a position closer to theaxis of the housings than the first conduit means, hammer means disposedwithin the first housing and rotatable about its axis, a chute connectedto the first housing at a position closer to the axis than the firstconduit means, and discharge means connected to the second housing at aposition closer to the axis than the second conduit means, the firstconduit means permitting a whirling gas stream produced in the firsthousing by the rotation of the hammer means to flow into the secondhousing and circulate about its axis therein, the second conduit meanspermitting a portion of the circulating gas to flow into the firsthousing, the discharge means serving to let the remainder of thecirculating gas out of the second housing, whereby a material fed to theinterior of the first housing is crushed by the hammer means and is thensent by the gas through the first conduit means into the second housingto circulate about its axis therein, the circulating material isclassified into coarse fragments and fine fragments by the cooperativeaction of centrifugal force and conveying force of the gas stream, thefine fragments are sent to the discharge means by the gas stream and thecoarse fragments are sent through the second conduit means into thefirst housing by the gas stream.
 2. An apparatus as set forth in claim 1wherein a plurality of guide vanes for the gas stream are provided inthe interior of the second housing in proximity to an opening of thefirst conduit means, each of the guide vanes being fixable and pivotableabout an axis substantially parallel to the axis of the second housing.3. An apparatus as set forth in claim 1 wherein a barrier plate isprovided to open the second conduit means to a variable extent.
 4. Anapparatus as set forth in claim 1 wherein an inner side surface of thesecond housing provided with the discharge means and opposed to theconduit means is slanted to constrict the interior space of the secondhousing toward the axis.
 5. An apparatus as set forth in claim 1 whereinan opening of the first conduit means to the second housing ispositioned further into the second housing than a corresponding openingof the second conduit means.
 6. An apparatus as set forth in claim 1wherein an outer edge portion of the second conduit means protrudes intothe first housing.
 7. An apparatus as set forth in claim 1 wherein, theinner surface of an outer portion of the second conduit means is slantedwith respect to the axis of the housings to enlarge the interior spaceof the second conduit means toward the first housing.
 8. An apparatus asset forth in claim 1 wherein both the conduit means are defined by apartition plate separating the housings from each other.
 9. An apparatusas set forth in claim 1 wherein a plurality of guide vanes for the gasstream are provided in the interior of the second housing in proximityto the opening of the first conduit means, each of the guide vanes beingfixable and pivotable about an axis substantially parallel to the axisof the second housing, an inner side surface of the second housingprovided with the discharge means and opposed to the conduit means isslanted to constrict the interior space of the second housing toward theaxis, the opening of the first conduit means to the second housing ispositioned closer to the second housing than a corresponding opening ofthe second conduit means, an outer edge portion of the second conduitmeans protrudes into the first housing, and, along a plane passingthrough the axis, the inner surface of the outer portion of the secondconduit means is slanted with respect to the axis of the housing toenlarge the interior space of the second conduit means toward the firsthousing.